Palimg is a perlbal plugin that allows you to modify GIF and PNG on the fly.
Put the images you want to be able to modify into the DOCROOT/palimg/ directory.
You modify them by adding /pSPEC to the end of the url,
where SPEC is one of the below defined commands (gradient,
tint,
etc).

You can change the gradient of the image by adding /pg0011111164ffffff to the end of the url. 00 is the index where the gradient starts and 111111 is the color (in hex) of the beginning of the gradient. 64 is the index of the end of the gradient and ffffff is the color of the end of the gradient. Note that all colors specified in hex should be lowercase.

You can tint the image by adding /pt000000aaaaaa to the end of the url. 000000 should be replaced with the color to tint towards. aaaaaa is optional and defines the "dark" tint color. Both colors should be specified as lowercase hex numbers.